1つのタブ内で日付を増やす方法は？

Question

私はアンドロイドの初心者です。私の仕事は、無限の時間にスワイプする1つのタブを持つアンドロイドアプリを作成することです。私の最初の画面は現在の日付を表示し、スワイプでは明日の日付に増分する必要があります。それを実装する方法を知っていません。私の友人を提案して案内してください。

ありがとうございます。

私の主な活動は、ここ

public class MainActivity extends AppCompatActivity { 

    /** 
    * The {@link android.support.v4.view.PagerAdapter} that will provide 
    * fragments for each of the sections. We use a 
    * {@link FragmentPagerAdapter} derivative, which will keep every 
    * loaded fragment in memory. If this becomes too memory intensive, it 
    * may be best to switch to a 
    * {@link android.support.v4.app.FragmentStatePagerAdapter}. 
    */ 
    private SectionsPagerAdapter mSectionsPagerAdapter; 

    /** 
    * The {@link ViewPager} that will host the section contents. 
    */ 
    private ViewPager mViewPager; 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_main); 


     // Create the adapter that will return a fragment for each of the three 
     // primary sections of the activity. 
     mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager()); 

     // Set up the ViewPager with the sections adapter. 
     mViewPager = (ViewPager) findViewById(R.id.container); 
     mViewPager.setAdapter(mSectionsPagerAdapter); 



    } 


    @Override 
    public boolean onCreateOptionsMenu(Menu menu) { 
     // Inflate the menu; this adds items to the action bar if it is present. 
     getMenuInflater().inflate(R.menu.menu_main, menu); 
     return true; 
    } 

    @Override 
    public boolean onOptionsItemSelected(MenuItem item) { 
     // Handle action bar item clicks here. The action bar will 
     // automatically handle clicks on the Home/Up button, so long 
     // as you specify a parent activity in AndroidManifest.xml. 
     int id = item.getItemId(); 

     //noinspection SimplifiableIfStatement 
     if (id == R.id.action_settings) { 
      return true; 
     } 

     return super.onOptionsItemSelected(item); 
    } 

    /** 
    * A placeholder fragment containing a simple view. 
    */ 
    public static class PlaceholderFragment extends Fragment { 
     /** 
     * The fragment argument representing the section number for this 
     * fragment. 
     */ 
     private static final String ARG_SECTION_NUMBER = "section_number"; 

     public PlaceholderFragment() { 
     } 

     /** 
     * Returns a new instance of this fragment for the given section 
     * number. 
     */ 
     public static PlaceholderFragment newInstance(int sectionNumber) { 
      PlaceholderFragment fragment = new PlaceholderFragment(); 
      Bundle args = new Bundle(); 
      args.putInt(ARG_SECTION_NUMBER, sectionNumber); 
      fragment.setArguments(args); 
      return fragment; 
     } 

     @Override 
     public View onCreateView(LayoutInflater inflater, ViewGroup container, 
           Bundle savedInstanceState) { 
      View rootView = inflater.inflate(R.layout.fragment_main, container, false); 
      TextView textView = (TextView) rootView.findViewById(R.id.section_label); 
      textView.setText(getString(R.string.section_format, getArguments().getInt(ARG_SECTION_NUMBER))); 
      return rootView; 
     } 
    } 

    /** 
    * A {@link FragmentPagerAdapter} that returns a fragment corresponding to 
    * one of the sections/tabs/pages. 
    */ 
    public class SectionsPagerAdapter extends FragmentPagerAdapter { 

     public SectionsPagerAdapter(FragmentManager fm) { 
      super(fm); 
     } 



     @Override 
     public int getCount() { 

      return 100; 
     } 


     @Override 
     public Fragment getItem(int position) { 
       Tab2 tab2=new Tab2(); 
       return tab2; 
     } 

     @Override 
     public CharSequence getPageTitle(int position) { 

        return "SECTION 3"; 

     } 

    } 
} 

ですそして、私のフラグメントの活動は、あなたが現在の日付に曜日を追加するフラグメントの位置を使用することができ、ここで

public class Tab2 extends Fragment { 
    String strDate; 
    @Nullable 
    @Override 
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, Bundle savedInstanceState) { 
     SimpleDateFormat sdf = new SimpleDateFormat("dd/MM/yyyy"); 

     for (int i = 0;i<=100;i++) { 
       if (i < 1) { 
        try { 
         Date myDate = sdf.parse("15/07/2017"); 
         Calendar c = Calendar.getInstance(); 
         c.setTime(myDate); 
         c.set(Calendar.DATE, c.get(Calendar.DATE) + 1); 
         Date newDate = c.getTime(); 
         strDate = sdf.format(newDate); 
        } catch (ParseException e) { 
         e.printStackTrace(); 

        } 
       } 
      else { 
        Date day = new Date(); 
        strDate = sdf.format(new Date(day.getTime())); 
       } 
     } 
     return inflater.inflate(R.layout.tab2,container,false); 
    } 
    @Override 
    public void onStart() { 
     super.onStart(); 

     TextView textView2 = getView().findViewById(R.id.textView2); 
     textView2.setText(strDate); 
    } 
} 

Answer 1

です。 最初のフラグメントの位置は0なので、0日を追加してください。 framentにpositionを送って、あなたのSectionPagerAdapterの中に今

public class Tab2 extends Fragment { 
    private int position; 


    public Tab2() { 
    } 

    public static Tab2 newInstance(int position) { 
     Tab2 fragment = new Tab2(); 
     Bundle args = new Bundle(); 
     args.putInt("position", position); 
     fragment.setArguments(args); 
     return fragment; 
    } 

    @Override 
    public void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     if (getArguments() != null) { 
      position = getArguments().getInt("position"); 
     } 
    } 

    @Override 
    public View onCreateView(LayoutInflater inflater, ViewGroup container, 
          Bundle savedInstanceState) { 
     return inflater.inflate(R.layout.fragment_t2, container, false); 
    } 

    @Override 
    public void onViewCreated(View view, @Nullable Bundle savedInstanceState) { 
     SimpleDateFormat sdf = new SimpleDateFormat("dd/MM/yyyy"); 
     Calendar c = Calendar.getInstance(); 
     c.add(Calendar.DAY_OF_MONTH, position); 
     String dt = sdf.format(c.getTime()).toString(); 


     TextView textView2 = getView().findViewById(R.id.textView2); 
     textView2.setText(dt); 
    } 

getItem方法：第2のフラグメントの位置はここ

は Tab2フラグメントのコード..です1であるので、その上の日付に1日を追加し、

@Override 
    public Fragment getItem(int position) { 
      return Tab2.newInstance(position); 
    }